The purpose of this circuit found in an old Elektor is to light a lower power lamp when the bigger one burns out. The loads depend on the triacs.
This circuit is from a 1968 Electronic Design. The components are from the era and the operating...
This circuit employs an old germanium transistor. The circuit is from a 1950s publication and uses...
Using a sensor from the time, this circuit was found in the 1992 Radio Electronics Handbook...